Recently, floppy disk systems have been developed that combine magnetic disk recording techniques with the high track capacity servos found in optical disk systems. Such a system is described in AN INTRODUCTION TO THE INSITE 325 FLOPTICAL(R) DISK DRIVE, Godwin, which was presented at the SPIE Optical Data Storage Topical Meeting (1989). Essentially, an optical servo pattern is pre-recorded on a magnetic floppy disk. The optical servo pattern typically consists of a large number of equally spaced concentric tracks about the rotational axis of the disk. Data is stored in the magnetic "tracks" between the optical servo tracks using conventional magnetic recording techniques. An optical servo mechanism is provided to guide the magnetic read/write head accurately over the data between the optical servo tracks. By utilizing optical servo techniques, much higher track densities are available on the relatively inexpensive removable magnetic medium.
As mentioned, the optical servo pattern typically consists of a large number of equally spaced concentric tracks about the rotational axis of the disk. As disclosed in U.S. Pat. No. 4,961,123, each track may be a single continuous groove (FIG. 3), a plurality of equally spaced circular pits (FIG. 8), or a plurality of short equally spaced grooves or stitches (FIG. 9). Various methods and systems exist for inscribing the optical servo tracks on the magnetic medium. For example, U.S. Pat. No. 4,961,123, entitled "Magnetic Information Media Storage With Optical Servo Tracks," discloses a method of an apparatus etching the servo track pattern on a disk using a laser.
U.S. Applications IOM-8721 and IOM-8723 (filed Jun. 10, 1992) show an apparatus and method for etching intermittent grooves in a floptical disk.
During laser etching of the floptical media, particulate waste is generated. The size of etching debris is in the order of micron or sub-micron. These fine etching debris remain on the floptical media surface as well as in the etched grooves after laser etching is completed. If the floptical medium is not cleaned, these debris damage both the floptical media and the read/write heads of the floptical drive.
Removal of laser etching debris from the floptical medium surface and grooves is a critical step in the manufacturing process. However, it is difficult to remove these microscopic or sub-microscopic debris from the floptical surface. Especially, it is harder to remove microscopic debris remaining in the stitches or grooves. In order to remove these microscopic debris, it has been attempted to wipe the etched floptical surface with synthetic cloth such as Rayon. The cloth was also used with a solution such as deionized water. However, much of the microscopic debris was not removed by this method, and the microscopic debris remained in the stitches. It has also been known in the relevant art that spraying a gas onto other recording media helps remove some undesirable materials. For example, Sno-Gun.TM. (Va-Tran Systems, Inc. Chula Vista, Calif.) has been used to remove dust from a magnetic floppy disk and flux from printed circuit boards and semiconductors. Sno-Gun.TM. sprays CO.sub.2 pellets onto a medium, Sno-Gun.TM. Cleaner, Description and Operating Instructions, Va-Tran Systems, Inc. While the nozzle of a Sno-Gun travels in a certain direction to remove the undesired materials from the medium, the medium remains stationary. When Sno-Gun.TM. was applied to a floptical medium as directed in the operating instructions, the removal of the microscopic debris was not complete. Moreover, during the spray cleaning, the low temperature freezes the surface of a floptical medium. This happens especially when the same area is repetitively sprayed with CO.sub.2 pellets. Thus, the effectiveness of Sno-Gun.TM. diminishes as more CO.sub.2 pellets are applied.
None of these prior art techniques solved or ever addressed the above mentioned problem of removing sub-microscopic or microscopic debris from the floptical medium after laser etching. Thus, the object of the current invention is to improve the removal of the microscopic and sub-microscopic debris from a floptical medium. Another object of the current invention is to prevent the floptical medium from being frozen during cleaning so that the microscopic debris removal remains effective. Yet another objective is to improve the microscopic debris removal by creating a larger energy disparity between the debris and the disk.